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This summer, we researched a mineral known as pyrrhotite, an iron-sulfide prone to oxidation and subsequent deterioration. It has been implicated in the cracking of foundations in homes across northeastern Connecticut. Such damage can require renovations running into the thousands and even hundreds of thousands of dollars. Therefore, pyrrhotite testing of concrete has been a major subject of focus in the Environmental Science Program, with the main objectives being to develop a comprehensive method for measuring pyrrhotite contamination and estimating probable-effect-concentrations.

Current Trinity sampling methods utilize a combination of X-Ray Diffraction (XRD), Carbon Nitrogen and Sulfur analysis (CNS), and magnetic susceptibility to determine mineralogy and sulfur concentration. In short, sulfur concentration is an indicator of pyrrhotite concentration, but pyrrhotite is not the only sulfur-bearing mineral present in concrete samples. Thus, the objective this summer was to determine the extent to which other sulfur-bearing minerals contribute to overall sulfur concentration. The process involved calibration/adjustment of the CNS analysis method in conjunction with XRD analysis. Our overall goal is to provide a more comprehensive quantification of pyrrhotite in concrete. We also worked on understanding the relationship between pyrrhotite and its oxidative products. Such knowledge is key to achieving better risk assessment as well as establishing a time scale for concrete deterioration.

Getting the dirt on urban ponds and streams

Bobbie collecting urban pond sediment

Ponds and streams can serve as critical habitats for wildlife in urban settings. However, they also can become ecological traps for wildlife if they are contaminated with toxins that decrease reproduction and survival. Wildlife can accumulate toxins through direct contact with the substances in the environment, as well as by consuming contaminated food sources such as plants and animal prey species. Shane and Bobbie took to the ponds, while Joe took to the streams, in parks in the Greater Hartford Area to explore contaminant levels in sediments and plants found within these ecosystems. Shane and Bobbie also assessed amphibian, reptile, and bird diversity in these ecosystems. They found that some ponds and stream segments were more impaired than others with contaminants such as mercury. Results were somewhat surprising though in that some of the most impacted ponds were located in the more beautiful, highly vegetated settings. It’s likely that those results were due to the application of lawn and gardening chemicals that contain mercury. These results suggest that use of such chemicals may pose a threat to wildlife in these habitats, as well as to people who recreate in and consume fish from these ecosystems.

Helping the hellbender

Shane, Bobbie, and I headed to Pennsylvania to continue research on hellbenders. Hellbenders are giant salamanders that live in streams and rivers in the eastern United States, from southern New York to northern Georgia, and west to Missouri. Their populations are declining throughout much of their range, and the Pitt lab has been researching the drivers of this decline so that we can better understand how to reverse these trends and conserve this species. Donning masks and snorkels, we took to the streams to survey the hellbender population.

Bobbie and Shane getting ready to snorkel.

While many hellbender populations show no signs of recruitment, our efforts uncovered a larval hellbender, indicating a healthy, reproducing population.

A larval hellbender we found.

Going to bat for bats

As an extra treat while in Pennsylvania, Shane, Bobbie, and I joined one of my former graduate students, Jamie Shinskie, for a night of bat surveys. Bat populations have declined precipitously due to white-nose syndrome, and an important step in conserving bats is to monitor their populations to understand how the populations are changing over time.

Shane setting up a mist net to catch bats.

One of the bats captured in the mist net.

Shane and Bobbie recording morphometric data for the bat researchers.

Oh Canada

With data and presentations in hand, Shane, Joe, and I headed to Canada to share the results of our research! Shane and Joe presented the urban pond and stream research and I presented hellbender research at the North American Congress for Conservation Biology in Toronto, ON. This professional scientific conference was attended by more than 800 people who specialize in conservation science, policy, and communication.

Shane and Joe explaining the urban pond and stream study.

Our group also took some time for bird watching while in Toronto…sort of. With the Rogers Centre just a few blocks from the conference venue, the group decided to take in a Blue Jays game. The Blue Jays may have lost that night, but our lab team shared a winning experience.

The goal of Nicole’s research is to see if it is possible to reconstruct a history of past fires through charcoal analysis. Charcoal is used as an indicator to reconstruct past fire dynamics and, when coupled with other paleoecological proxies, can be used to enhance paleoecological reconstructions.

Soil profile HNC 15-G

The soil samples come from a series of locations within the Hitchcock Nature Center in Pottawattamie County, Iowa (41.4209°N, -95.8659°W). The samples were collected at 5 cm intervals up to a depth of 2.3 meters at each location. A small amount of each sample was mixed with 0.10 M KOH solution in a centrifuge tube. The tubes were then placed in an ultrasonic bath to break up soil fragments and was then passed through a 180 mm screen. The coarse fraction was rinsed with deionized H2O to remove any fine particles and the remaining sample transferred to a petri dish. Charcoal was identified at 20x magnification under a microscope and separated from the rest of the sediment sample for analysis. Charcoal particles were photographed, and their surface area was determined through image analysis performed in ImageJ.

This is what macroscopic charcoal looks like.

Charcoal concentrations are reported in mm2/g. The soil profile was dated using four radiocarbon ages obtained from charcoal fragments and snail shells. All soil ages were in chronological order and the oldest soil samples were approximately 780 years old. Prior to approximately 1870 average charcoal concentrations are low and relatively consistent in most samples.

An image of Nicole’s soil profile, several magnetic parameters, and Nicole’s charcoal counts (in brown). The spike in charcoal occurred approximately at the end of the 19th century.

At a depth of 30 cm below surface, there was a spike in the amount of charcoal up that is higher than most of the rest of the sample. This spike dates to approximately 140 years ago and its timing correlates with the onset of large-scale settlement of Pottawattamie County by European settlers. Settlers likely burned the original forest and grasslands to create viable land for farming. After this initial spike, the level of charcoal decreases but continues to stay elevated. This could be a result of less frequent burning to keep the unwanted biomass at bay.

In April the City of Hartford asked for help with their tree planting efforts. No, they did not ask for a bunch of kids who’d go out into the neighborhoods, digging holes, and planting trees. They wanted to know how many trees Hartford would have to plant in order to maintain its current canopy cover of 26% or to expand it to 35%.

This question is a little bit less straightforward than one might think, and the answer turned out to be a bit complicated. Luckily, we found Giles Lemmon (’21), who likes environmental problems and data crunching and had no current summer plans. We easily talked him into working as an intern for the City of Hartford. There he worked with Grace Li from the City’s Sustainability Office and Jack Hale, the chair of Hartford’s Tree Advisory Commission. Hartford’s trees follow a rather irregular age distribution, which means that the loss of large, mature trees is not simply compensated by planting an equal number of small trees. In addition, poor and spotty data made Giles’ job even more challenging.

Working with iTree, an open source software package developed in collaboration with the US Forest Service, Giles found that planting trees at a rate of 1000 / year would lead to a canopy loss of 440 acres (9 times the size of Bushnell Park) over the next 30 years. To maintain present canopy cover, he estimates that one would have to plant approximately 1500 trees per year, and an increase in canopy cover to 35% within the next 30 years would require an annual planting of approximately 7000 trees.

At this week’s science symposium we enjoyed two talks from our ENVS majors. Joe Ruggiero presented work on his research on pyrrhotite in Connecticut metamorphic rocks and how it affects the stability of concrete. Pyrrhotite acts as a source of sulfate which can lead to internal sulfate attack (ISA) in concrete foundations. ISA due to pyrrhotite-containing aggregate is the cause of premature concrete failure which affects thousands of homes in northeastern Connecticut.Sarah Messenger, an ENVS / BIOL double major, presented her work on permeable reactive barriers and their role in controlling nitrate inputs into estuaries. Sarah’s thesis started out as a semester-long research project with MBL at Woods Hole. She continued her study on the efficacy of these barriers and is currently working with Dr. Lisa Foster identifying the bacterial communities involved in nitrate reduction.

Hi! I’m Dr. Krista Ehlert and I’m the Thomas McKenna Meredith ’48 Postdoctoral Fellow in Environmental Science (phew!). My students and I have a plethora of diverse, but connected, research projects. The Ehlert lab at Trinity is focused on ecologically based management of invasive plants, with a special focus on Berberis thunbergii, Japanese barberry. Specifically, we’re looking at the intersection between Japanese barberry, Ixodes scapularis (the black-legged tick), climate change, and Lyme disease. Forests invaded with Japanese barberry have twice as many ticks as those that aren’t; this is associated with the fact that Japanese barberry creates the ideal, humid environment that ticks need to avoid desiccation. Here’s a closer look at what we’ve already completed and are currently investigating in the Ehlert lab:

Recent ENVS alum Adam assessed different survey methods of Japanese barberry in Simsbury, CT. Adam specifically used transects and GIS to quantify the extent of invasion at our study site. Along each 50 m transect, Adam utilized a quadrat to count Japanese barberry density and cover. With GIS, Adam downloaded NDVI (normalized difference vegetation index) satellite data to map Japanese barberry locations, as you can see in the map below. The NDVI values closely align with the dense shrubbery that we associated with Japanese barberry from Adam’s transects.

Blair, another recent ENVS alumna, investigated the invasivore movement, specifically as it related to Japanese barberry. The invasivore movement is a means of eradicating invasive species through human consumption. In the past, the fruit of Japanese barberry has been used to make…jam! Blair went to work by first conducting a strong literature review of the invasivore movement and how it became popularized. Next, she spent time in the kitchen! Blair was able to successfully produce jam from Japanese barberry, providing an alternative means of controlling this insidious invader.

Blair holding the jam she produced from Japanese barberry fruit, alongside the poster she presented at the student research colloquium in Spring 2017.

Soon to be ENVS alumna Corinne and I are investigating the role of horses as potential vectors of invasive plant seeds. Corinne and I are interested in this research question because we each have a horse! Horses are able to transport invasive seeds not only through their digestive tract, with seeds ending up in their feces (eek!), but their manes, tails, and fur can also easily transport seeds. We’re focusing on the latter for Corinne’s research. Corinne started her research by conducting a survey of Intercollege Horse Show Association (IHSA) horseback riders, to learn about their attitudes toward and knowledge of invasive plants. We will be expanding upon the survey by conducting experiments with our own horses and others to investigate how far seeds can travel when attached to their fur.

Corinne presenting the results of her survey at the student research colloquium in Spring 2017.

Another soon to be alumna, Bailey from the Biology department, spent the summer along with Blair helping me with the Japanese barberry research (see previous blog post!). Bailey will be expanding on this research for her senior thesis in the Biology department, and will be co-advised by Dr. Amber Pitt and I. Specifically, Bailey will be focusing on the effect of microhabitat on black-legged tick abundance on the white-footed mouse, Peromyscus leucopus. White-footed mice are reservoirs of Borrelia burgdorferi, the bacteria that causes Lyme disease. Ticks feed on mice for one of their blood meals, become infected, and move on to their next blood meal – often a human, thereby transmitting Lyme disease. Bailey will accomplish this research by using live-catch traps in the field, and counting tick load on each captured mouse; after counting is complete, the mouse will be released back into the wild. Overall, we hope that Bailey’s project sheds light on tick load on white-footed mice in a Japanese barberry infested forest.

Biology student Bailey in the field with a Japanese barberry shrub that has been uprooted.

That’s a wrap on what the Ehlert lab has accomplished and is currently doing! I’m actively looking for one or two research students this fall to help on the Japanese barberry project, so if you’re interested, send me an email at: krista.ehlert@trincoll.edu or stop by McCook 123! Or stop by if you’re interested in other invasive plant research!

This summer, Dr. Krista Ehlert and her research students have been investigating the role of in situ climate change on different management strategies for Japanese barberry (Berberis thunbergii), and how that in turn, affects the black-legged tick (Ixodes scapularis), which serves as a reservoir for Lyme disease. The two summer research students in the Ehlert lab are ENVS alumna Blair Frantz ’17 and Biology student Bailey D’Antonio ’18. A lot of the work we’ve done so far has been setting up open top climate chambers (OTCs) that utilize the greenhouse effect to increase the temperature inside the chamber by 1-3°C – what models are estimating with climate change. We also employed different management strategies for Japanese barberry, such as pulling the plant and applying herbicide and compared those to an untreated control. The data that we’ve collected includes vegetation surveys, temperature recordings, and ticks! This data will continue to be collected into the fall, and once we have a few hundred-ish (or more) ticks, we’ll be testing them for Lyme disease. Overall, we’ve had a great summer and are excited to uncover more about the indirect effect Japanese barberry has on Lyme disease incidence in Connecticut. If you want to learn more about what the Ehlert lab is up to follow us on Instagram @ thescientificlunaticks.

I am spending this semester at the Marine Biological Laboratory (MBL) in Woods Hole, MA doing a program called Semester in Environmental Science. Being the first Trinity student to do SES I had no idea what to expect. The answer is SES is amazing. So far I’ve had the chance to learn from scientists who are doing some amazing research on climate change, do some awesome field work, hang out with other science geeks, live on the beach, and eat obscene amount of lobster at the dining hall.

That’s not to say the program isn’t intense. We’ve done more field, lab, and data work up in the last fifteen days than I’ve done in a full semester. We collect data in both terrestrial and aquatic systems meaning I’ve had the chance to try my hand at some cool data collection techniques and equipment. Already I feel like I have a better understanding of how to design experiments and collect meaningful data in order to answer research questions. Even more important, we spend a lot of time working with our data in excel. As a result I not only know how to collect data but I know what to do with it afterwards. I 100% recommend SES to any environmental science (or biology or chemistry) majors who are interested in pursuing research in the future. If you’re interested in applying or just want to learn more please shoot me an email. I’m having the time of my life and would love to see more Trinity students take advantage of this opportunity.

Students presenting the results of their summer research at the Science Symposium

Today, during lunch hour, Jon’s summer research students Cassia, Jack and David presented the results of heir summer research to the wider College community. They had three posters outlining their ongoing research on the effects of clear cutting on Mercury, Aluminum and Calcium concentrations in forest soils. This research project, now in its second year, continues research initiated by Justin and Dan.

David presenting introductory information on the ongoing White Mountain research project.

Cassia and Jack showed some of the first results. Cassia focused on changes in organic matter and mercury, while Jack presented data on Aluminum and Calcium.

Jack and Cassia explaining the results of their summer work.

Just in case you wondered: yes, Cameron’s crew was pretty busy too all summer. Jordyn presented their research in a poster presentation at the annual meeting of the Ecological Society of America (ESA) in Baltimore.